the negative expression of survivin protein and HIF-1α protein, respectively, in benign lung disease tissues. C and D represent the positive expression (arrow) of survivin protein and HIF-1α protein, respectively, in NSCLC,. E: The graph shows the statistical results. 81.60% (98/120) of lung cancer tissue samples were positive for survivin staining, and 58.33% (70/120_) of lung cancer tissue samples were positive for HIF-1α staining. ** p < 0.01. Hypoxia induces expression of HIF-1α and survivin When A549 cells were incubated in hypoxic conditions for 24 h, the expression of HIF-1α Etofibrate (2B, C, D) and survivin (2A, C, D) were detected by quantitative real time, reverse transcription-PCR (2A, B) and western blot (2 C, D). As shown in Fig 2, the expression of survivin and HIF-1α was increased significantly in hypoxia as compared to normoxia (p < 0.01). Figure 2 Hypoxia induces expression of HIF-1α and survivin. A549 cells were cultured in 10% FBS medium under hypoxic or normoxic conditions for 24h. The relative levels of survivin (A) and HIF-1α (B) to GAPDH mRNA were determined by quantitative

real time, reverse transcription-PCR. C: The expression of survivin and HIF-1α protein in A549 cells following HIF-1α-siRNA treatment as detected by Western blot analysis. D: The graph shows the statistical results of relative expression level of survivin and HIF-1α to β-actin protein. Data are given as means ± SD, n = 3, ** p < 0.01. Site directed mutagenesis of HIF-1α binding site on the survivin promoter decreases transcription activity of the survivin promoter To determine whether the binding-site of HIF-lα can affect the transcription of survivin in A549 cells, the GTGC sequence in -19 ~ -16 bp of survivin promoter (Fig. 2A) was changed to AGC by site-directed mutagenesis, and the relative activity of the normal and mutated survivin promoter were detected by luciferase activity assay. As shown in Fig.